Could the advent of electronic texts mark the death of books, for so long the staple fare of university libraries and college students? This will be one of the key discussions at a major conference on the future of textbooks at London's City University tomorrow.

Publishers, university librarians, authors and vice-chancellors are meeting to explore the issues facing academic publishing in the wake of the internet, digital publishing and the government's ambition to increase the number of 18-year-olds participating in higher education to 50% by 2006.

During the past five years there has already been one revolution in the academic publishing industry. Textbooks in the UK used to be published in parallel, split editions - a relatively expensive hardback for university libraries, and a much cheaper, cross-subsidised paperback for student purchase. Now, however, libraries buy paperbacks, the cross-subsidies have ceased, and the hardback undergraduate textbook has virtually disappeared. The cost of paperbacks has now risen.

Dr Iain Stevenson, director of publishing studies at City University, who is chairing the conference, says: "No one does parallel editions now. If the hardback goes, quite a large revenue stream has gone."

Dr Stevenson is worried that publishers are concentrating on producing high-volume textbooks for large numbers of first-year undergraduates studying subjects such as law, psychology, economics and sociology, and not producing books for second-year, third-year and postgraduate students.

In several areas of academic publishing, where texts are especially expensive to produce - for example, modern languages, mathematics and medicine - a dwindling number of publishers are producing undergraduate texts.

Publishers are also worried by the way lecturers are now using academic texts. Not so long ago, they would issue book lists recommending key texts - which students then bought - and supplementary reading in the university library. Now lecturers are pro ducing course packs pulling together copyright learning materials from a number of sources including a variety of textbooks. This is partly because of student poverty and partly because of the rise of the student as customer.

There is a demand, Dr Stevenson adds, for ready-processed material shaped to the exact demands of a specific course. This has resulted in a process known as "slicing and dicing".

"If you are a law lecturer at a big former polytechnic, you might get a chapter out of a textbook published by Sweet and Maxwell, another from a textbook published by Butterworth, a third from one published by Cavendish and a fourth from a book published by OUP," Dr Stevenson says. "Then you link these together with bits and pieces you put in yourself from various other sources, put all this into one big pot, stir it around and give it to the students." The issue has led some publishers to threaten to withdraw from textbook publishing altogether, he says.

But perhaps the biggest issue for the future is whether electronic versions of textbooks will supplant the traditional paper versions. E-books have the advantages of being easily searched and annotated, instantly accessible, portable and capable of being linked to other multimedia. Dictionaries, encyclopaedias and techni cal manuals are especially suited to being published in electronic form.

Dr Hazel Woodward, university librarian at Cranfield and chair of the Joint Information Services Committee's e-books working group, says that most publishers now have electronic versions of their books and that some are digitising their back-lists as well.

The problem for university libraries is that buying e-books from publishers is scarcely affordable at present because publishers are trying to sell universities bundles of books rather than on a title-by-title basis.

She says publishers are afraid libraries would buy one electronic copy of a book, then make it available to many students via the library catalogue 24 hours a day, seven days a week - one payment instead of multiple payments from libraries and individual students.

"Getting that economic model right is really perplexing us at the moment," Dr Woodward says. "How do we decide what is fair? Publishers want to preserve their revenue stream, but in a way that is affordable to libraries."

The economic model is certainly a problem for publishers. Another type of e-books supplier, an aggregator-type such as NetLibrary, acquires electronic books from various publishers, then, acting as an intermediary, sells them on to libraries. NetLibrary, how ever, went bankrupt in November and was bought by the non-profit Online Computer Library Center to safeguard the investment of thousands of libraries around the world.

Rod Bristow, president of Pearson Education UK, the leading textbook publisher in the UK, believes there will be no diminution in the role of the textbook. "It's very hard to deliver what you get in a textbook more effectively in other ways. Textbooks are extremely convenient," he says.

Pearson lost an eyewatering £83m in 2000 on its e-learning project, Learning Network, but is developing electronic libraries in which students can read around their subject, look up relevant articles, update material, and work interactively and with simulations. It is also helping lecturers to deliver courses via learning management systems that test and record the progress of individual students.

"I think you will see a multiplicity of media in future, rather than one medium replacing another. If you look at the history of media in general, when a new medium comes along, it does not usually replace an earlier one; it just adds to it.

"Books came first, then radio, cinema, video and computing. None of these things has replaced the book. That's great because it enriches choice for the customer."